Steroids significantly weaken connective tissue and thereby increase the chance of muscle tears whose damage is permanent & irreversible.
I've also wondered about this. No matter how hard and heavy, or for how long you lift weights, if you are effectively a blow up doll with most of your muscle 'mass' coming from hormones/peptides your connective tissue and tendons will never be as 'strong' as your inflated muscles. Sure you will be able to bench 4 plates a side because of the sheer size of your glycogen filled pecs, but when 400 pounds is pulling on much smaller areas such as tie-ins and tendons it will give eventually.
Obviously form plays a big part, and a lot of tears shouldn't have happened, but it does make you wonder.